import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter_webview_plugin/flutter_webview_plugin.dart';
const CATCH_URLS=['m.ctrip.com/','m.ctrip.com/html5/','m.ctrip.com/html5'];

class WebView extends StatefulWidget {
  final String url;
  final String statusBarColor;
  final String title;
  final bool hideAppBar;
  final bool backForbid;


  WebView({this.url, this.statusBarColor, this.title, this.hideAppBar,this.backForbid=false});

  @override
  _WebViewState createState() => _WebViewState();
}

class _WebViewState extends State<WebView> {
  final webviewReference=FlutterWebviewPlugin();
  StreamSubscription<String> _onUrlChanged;
  StreamSubscription<WebViewStateChanged> _onStateChanged;
  StreamSubscription<WebViewHttpError> _onHttpError;
  bool exiting=false;
  @override
  void initState() {
    // TODO: implement initState
    super.initState();
    webviewReference.close();
    webviewReference.onUrlChanged.listen((url){

    });
    _onStateChanged=webviewReference.onStateChanged.listen((WebViewStateChanged state) {
      switch(state.type){
        case WebViewState.startLoad:
          if(_isToMain(state.url) && !exiting){
            if(widget.backForbid){   //禁止返回
              webviewReference.launch(widget.url);
            }else{
              Navigator.pop(context);
              exiting=true;
            }
          }
          break;
        default:
          break;
      }
    });
    _onHttpError=webviewReference.onHttpError.listen((WebViewHttpError error) {
      print(error);
    });
  }

  _isToMain(String url){
    bool contain=false;
    for(final value in CATCH_URLS){
      if(url?.endsWith(value)??false){
        contain=true;
        break;
      }
    }
    return contain;
  }
  @override
  void dispose() {
    // TODO: implement dispose
    _onStateChanged.cancel();
    _onUrlChanged.cancel();
    _onHttpError.cancel();
    webviewReference.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    String statusBarColorStr=widget.statusBarColor??'ffffff';
    Color backButtonColor;
    if(statusBarColorStr=='ffffff'){
      backButtonColor=Colors.black;
    }else{
      backButtonColor=Colors.white;
    }
    return Scaffold(
      body: Column(
        children:<Widget> [
          _appBar(Color(int.parse('0xff'+statusBarColorStr)),backButtonColor),
          Expanded(child: WebviewScaffold(url: widget.url,
          withZoom: true,
          withLocalStorage: true,
          hidden: true,
          initialChild: Container(
            color: Colors.white,
            child: Center(
              child: Text('Waiting....'),
            ),
          ),))
        ],
      ),
    );
  }
  _appBar(Color backgroundColor,Color backButtonColor){
    if(widget.hideAppBar??false){
      return Container(
        color: backgroundColor,
        height: 30,
      );
    }
    return Container(
      color: backgroundColor,
      padding: EdgeInsets.fromLTRB(0, 40, 0, 10),
      child: FractionallySizedBox(
        widthFactor: 1,
        child: Stack(
          children: <Widget>[
            GestureDetector(
              onTap: (){
                Navigator.pop(context);
              },
              child: Container(
                margin: EdgeInsets.only(left: 10),
                child: Icon(
                  Icons.close,
                  color: backgroundColor,
                  size: 26,
                ),
              ),
            ),
            Positioned(
              left: 0,
              right: 0,
              child: Center(
                child: Text(widget.title??'',
                style: TextStyle(color: backgroundColor,fontSize: 20),),
              ),
            ),
          ],
        ),
      ),
    );
  }
}
